\documentclass{article}

\usepackage{multirow}
\begin{document}

\begin{table}[!h]
\centering\renewcommand\arraystretch{1.2}
\begin{tabular}{c|c|c}
\hline
Topic 1 & \multicolumn{2}{c}{Topic 2}\\
\hline
33333 & 44444 & \multirow{2}{*}{55555}\\
\cline{1-2}
aaaaa & bbbbb\\
\hline
 \end{tabular}
\caption{}
  \label{table:example-app}
\end{table}

\end{document} 
